JP2012021619A - Compressor seal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compressor seal device that can maintain air tightness on a compressor impeller side at the stop of a rotating shaft.SOLUTION: The compressor seal device having a kinetic pressure generation groove 3b at a rotating ring 3 includes: the rotating ring 3 coaxially attached to the rotating shaft 1; a static ring 9 which coaxially opposes the rotating ring 3; a holder 8 which is attached to a compressor housing 7 so as to surround the static ring 9 in the circumferential direction, and movably supports the static ring 9 to the axial direction; and a spring 11 which biases the static ring 9 toward the rotating ring 3. An auxiliary ring 4 is externally fit to the rotating shaft 1 while leaving an air gap 12 apart from the inner circumferential surface of the holder 8. A seal ring 18 attached with a seal member 17 which can seal the air gap 12 between the auxiliary ring 4 and the holder 8 over the whole circumference is arranged so as to oppose the auxiliary ring 4 and the end face at a side opposite to the rotating ring 3 of the holder 8, and a driver 19 for pushing out the seal ring 18 toward the auxiliary ring 4 and the holder 8 is arranged.

Description

  The present invention relates to a compressor seal device.

  As a compressor seal device for suppressing gas leakage from the compressor impeller side to the outside of the housing, there is one called a dry gas seal or a non-contact mechanical seal. An example of a non-contact mechanical seal is a patent document. 1 is disclosed.

The non-contact mechanical seal is
A rotating ring attached to the middle portion in the longitudinal direction of the rotating shaft having an impeller on the tip side;
A stationary ring mounted on the housing so that it can move minutely in the axial direction relative to the rotating ring;
A spring for biasing the stationary ring toward the rotating ring,
A dynamic pressure generating groove extending in a radially curved manner is formed in the outer edge portion of the end face to which the stationary ring of the rotating ring faces.

  In the non-contact mechanical seal of Patent Document 1, when the rotating shaft is stopped, the stationary ring is pressed against the rotating ring by a spring. When the rotating shaft starts to rotate, both rotate while the stationary ring is pressed against the rotating ring. However, if the rotational speed of the rotating ring exceeds a predetermined value, the rotating ring is driven by the gas taken into the dynamic pressure generating groove. The dynamic pressure generated between the end surfaces of the stationary ring overcomes the urging force of the spring and causes the stationary ring to be slightly displaced in the direction away from the rotating ring.

  As a result, the rotating ring and the stationary ring rotate with a slight sealing gap (about 2 μm) between both end faces, and wear due to the sliding of the rotating ring and the stationary ring with each other is avoided. In addition, the amount of gas leaking from the compressor impeller side to the outside of the housing through the seal gap is minimized.

Japanese Patent Laid-Open No. 03-140672

  In the case where the gas pressurized by the compressor using the non-contact mechanical seal of Patent Document 1 is flammable, auxiliary flammable, or toxic, the gap between the rotating ring and the stationary ring during the operation of the compressor. Separate vacuum suction means for collecting leaked gas and preventing its release into the atmosphere, and inert gas blowing supply means for diluting flammable and auxiliary gas with inert gas (for example, nitrogen gas) It is necessary to provide in.

  In addition, when the compressor is stopped, the stationary ring is pressed against the rotating ring by the spring, and the airtightness on the compressor impeller side should be maintained. Since there is a gap, gas leakage cannot be completely prevented.

  For this reason, in a compressor targeting flammable, auxiliary combustion, and toxic gases, the vacuum suction means and the inert gas blowing supply means are operated even when the compressor is stopped, Gas diffusion is prevented or gas is diluted, and power costs for the vacuum compression means and the inert gas blowing means are always applied.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a compressor seal device that can maintain airtightness on the compressor impeller side when the rotary shaft is stopped.

In order to achieve the above object, the invention described in claim 1
A rotating ring mounted coaxially on the rotating shaft;
A stationary ring coaxially opposite the rotating ring;
A holder mounted on the housing so as to surround the stationary ring in the circumferential direction and supporting the stationary ring so as to be movable in the axial direction;
A spring for biasing the stationary ring toward the rotating ring,
The auxiliary ring is externally fitted to the rotating shaft so as to separate the gap from the inner peripheral surface of the holder,
In the compressor seal device provided with the dynamic pressure generating groove on one of the opposed surfaces of the rotating ring and the stationary ring,
The end surface on the counter-rotating ring side of the auxiliary ring is formed so as to be flush with the end surface on the counter-rotating ring side of the holder,
On the counter-rotating ring side of the auxiliary ring and the holder, a seal ring equipped with a seal member capable of sealing the gap between the auxiliary ring and the holder over the entire circumference is arranged,
When the compressor is in operation, the seal ring is pushed out toward the auxiliary ring and the holder so that the gap is sealed by the seal member. When the compressor is stopped, the seal ring is removed from the auxiliary ring and the holder so that the gap is not blocked by the seal member. A driving means for separating is provided.

The compressor seal device according to claim 2 is:
An O-ring is used as the seal member, and a groove into which the O-ring is fitted is formed in the seal ring.

  According to the compressor seal device of the present invention, the following excellent effects can be obtained.

  (1) In any one of the compressor sealing devices according to claims 1 and 2, when the seal ring is pushed out toward the auxiliary ring and the holder by the driving means, the seal member mounted on the seal ring becomes the auxiliary ring and the holder. Since the gap is sealed over the entire circumference, the airtightness on the compressor impeller side can be maintained.

  (2) In the compressor sealing device of the second aspect, since the O-ring is used as the sealing member, when the sealing ring is pushed out by the driving means, the sealing member is easily adapted to the auxiliary ring and the holder, and the gap is surely secured. Can be blocked.

(A) is sectional drawing which shows the state which is pressing the O-ring for gap sealing in the 1st example of the compressor sealing apparatus of this invention, (b) is the press of the O-ring for gap sealing in (a). It is sectional drawing which shows the state which cancelled | released. FIG. 2 is a partial cutaway view of the seal ring in FIG. 1 as viewed in the axial direction. It is the figure which looked at the contact end surface of the rotary ring in FIG. 1 in the axial direction. (A) is sectional drawing which shows the state which is pressing the O-ring for gap sealing in the 2nd example of the compressor sealing apparatus of this invention, (b) is the press of the O-ring for gap sealing in (a). It is sectional drawing which shows the state which cancelled | released.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 (a), (b), FIG. 2 and FIG. 3 show a first example of a compressor seal device of the present invention. In a longitudinal intermediate portion 1c of a rotary shaft 1 having an impeller on the tip A side. The sleeve 2 is externally fitted, and the rotary ring 3 having the contact end surface 3a facing the base end B side of the rotary shaft 1 is fitted to the sleeve 2 so that the rotary ring 3 is coaxially mounted on the rotary shaft 1. . The rotation of the output shaft of the main motor (not shown) is transmitted to the rotating shaft 1 through the speed increasing mechanism. As the rotating ring 3, for example, a stainless steel base material formed with a coating layer made of a material that is difficult to wear, such as titanium nitride, is used. In addition, the dashed-dotted line in FIG. 1 and FIG. 4 mentioned later shows the centerline of the rotating shaft 1. FIG.

  The rotating shaft 1 is formed as a large-diameter portion 1a having a diameter larger than that of the longitudinal intermediate portion 1c on the distal end A side with respect to the longitudinal intermediate portion 1c to which the sleeve 2 and an auxiliary ring 4 described later are fitted. The base end B side of the direction intermediate portion 1c is formed as a small diameter portion 1b having a smaller diameter than the longitudinal direction intermediate portion 1c.

  The sleeve 2 is formed in a shape that covers the inner peripheral surface of the rotary ring 3, the outer peripheral surface of the rotary ring 3, and the surface of the rotary ring 3 that faces the tip A side of the rotary shaft 1. A restriction pin 5 parallel to the rotation shaft 1 is fitted into the sleeve 2 and the rotation ring 3, and the restriction pin 5 plays a role of stopping the displacement of the rotation ring 3 in the circumferential direction with respect to the sleeve 2.

  An auxiliary ring 4 whose end surface facing the tip A side of the rotating shaft 1 is in contact with the inner edge portion of the contact end surface 3a of the rotating ring 3 is fitted on the intermediate portion 1c in the longitudinal direction of the rotating shaft 1, and the small-diameter portion of the rotating shaft 1 The auxiliary ring 4 is pressed against the rotating ring 3 by screwing and tightening the nut 6 to 1b.

  A holder 8 surrounding the auxiliary ring 4 in the circumferential direction is fastened to the compressor housing 7 with a bolt 8 a, and a stationary ring 9 having a contact end face 9 a facing the tip A side of the rotary shaft 1 is supported inside the holder 8. For the stationary ring 9, for example, a material having excellent slidability such as carbon is used.

  The holder 8 is provided with a guide pin 10 for guiding the stationary ring 9 in the direction of approaching and moving away from the rotating ring 3 by positioning the stationary ring 9 coaxially with the rotating ring 3 and the stationary ring 9 facing the rotating ring 3. The spring 11 is energized, and the spring 11 plays a role of pressing the contact end surface 9a of the stationary ring 9 against the contact end surface 3a of the rotating ring 3 when the compressor is stopped.

  The outer peripheral surface of the auxiliary ring 4 that is externally fitted to the rotary shaft 1 separates a gap 12 with respect to the inner peripheral surface of the holder 8, and the gap 12 extends from the proximal end B side to the distal end A side of the rotary shaft 1. When looking toward it, it has a circular shape.

  On the outer edge portion of the contact end surface 3a of the rotary ring 3, a dynamic pressure generating groove 3b that is curved and extends radially is formed.When the rotational speed of the rotary ring 3 exceeds a predetermined value as the compressor starts operating, The dynamic pressure generated between the rotating ring 3 and the contact end surfaces 3a, 9a of the stationary ring 9 by the gas taken into the dynamic pressure generating groove 3b overcomes the urging force of the spring 11, and the stationary ring 9 is removed from the rotating ring 3. It is designed to be slightly displaced in the direction of separation.

  Reference numeral 13 denotes a seal member interposed between the large-diameter portion 1a of the rotary shaft 1 and the sleeve 2, reference numeral 14 denotes a seal member interposed between the sleeve 2 and the rotary ring 3, and reference numeral 15 denotes Reference numeral 16 denotes a seal member interposed between the sleeve 2 and the auxiliary ring 4. Reference numeral 16 denotes a seal member interposed between the stationary ring 9 and the holder 8, and these seal members 13, 14, 15, 16 Uses an O-ring.

  1 (a), 1 (b), FIG. 2 and FIG. 3 are characterized in that the end surface of the auxiliary ring 4 on the side opposite to the rotating ring 3 (the counter rotating ring side) is It is formed so as to be in the same plane as the end face on the opposite side (counter-rotating ring side) from the rotating ring 3, and on the end face on the opposite side (counter-rotating ring side) of the auxiliary ring 4 and holder 8 A seal ring 18 fitted with a seal member 17 capable of sealing the gap 12 between the auxiliary ring 4 and the holder 8 over the entire circumference is disposed so as to face each other, and the seal ring 18 faces the auxiliary ring 4 and the holder 8. The driving means 19 for pushing out is provided.

  An O-ring is used for the seal member 17, and a groove (for example, dovetail groove) 20 into which the O-ring is fitted is formed in the seal ring 18.

  Three or more guide pins 21 projecting in parallel with the rotary shaft 1 are provided on the end surface of the holder 8 opposite to the rotary ring 3, and a pin hole 22 through which the guide pin 21 is inserted in the seal ring 18. , And the seal ring 18 approaches and separates from the auxiliary ring 4 and the holder 8 along the guide pin 21. The reason why there are three or more guide pins 21 is to keep the end face of the seal ring 18 parallel to the auxiliary ring 4 and the holder 8 so that the seal ring 18 moves smoothly.

  The drive means 19 has a rod 23 that protrudes toward the end surface of the seal ring 18 opposite to the rotary ring 3 and can be advanced and retracted in a direction parallel to the rotary shaft 1 by a servo motor. The drive means 19 is attached to and attached to the compressor housing 7 for each guide pin 21 so that the rod 23 does not interfere with the guide pin 21, and the tip of the rod 23 is fastened to the seal ring 18. The drive means 19 is provided for each guide pin 21 so that the seal ring 18 fitted with the seal member 17 is evenly pushed toward the auxiliary ring 4 and the holder 8.

  Next, the operation of the compressor seal device shown in FIGS. 1A, 1B, 2 and 3 will be described. When the rotating shaft 1 is stopped, the stationary ring 9 is pressed against the rotating ring 3 by the spring 11, and both contact end faces 3a, 9a of the rotating ring 3 and the stationary ring 9 are in contact with each other. .

  When operating the compressor, the rod 23 of the driving means 19 is retracted, the seal ring 18 is separated from the auxiliary ring 4 and the holder 8, and the gap 12 between the auxiliary ring 4 and the holder 8 is attached to the seal ring 18. The seal member 17 is not sealed.

  In a compressor provided with vacuum suction means for preventing flammable, auxiliary combustion, and toxic gas from being pressurized as described above and preventing the gas from being released into the atmosphere as described above, the vacuum suction means is operated. .

  When the main motor is operated and the rotating shaft 1 starts to rotate, the rotating ring 3 and the stationary ring 9 are relatively slipped up to a predetermined number of rotations, but the number of rotations of the rotating ring 3 has a predetermined value. If it exceeds, the dynamic pressure generated between the contact end faces 3a, 9a of the rotating ring 3 and the stationary ring 9 by the gas taken into the dynamic pressure generating groove 3b overcomes the urging force of the spring 11, and causes the stationary ring 9 to rotate. A slight displacement is made in a direction away from 3.

  Thereby, the rotating ring 3 and the stationary ring 9 are rotated by forming a slight seal gap (about 2 μm) between the contact end faces 3a and 9a, and the rotating ring 3 and the stationary ring 9 slide relative to each other. The wear caused by this is avoided, and the seal member 17 does not close the gap 12 between the auxiliary ring 4 and the holder 8, so wear caused by the sliding of the auxiliary ring 4 and the seal member 17 is also avoided. Is done.

  When the seal gap is formed, a small amount of gas from the compressor impeller side causes the rotating ring 3 and the stationary ring 9 to seal between the contact end surfaces 3a and 9a of both the two, and between the auxiliary ring 4 and the holder 8. Although it leaks out of the compressor housing 7 through the air gap 12, in a compressor whose pressure is increased by flammable, auxiliary combustion, and toxic gas, by operating the vacuum suction device described above, Prevents gas emission.

  When the operation of the main motor is interrupted and the rotating shaft 1 is stopped, gas is not taken in by the dynamic pressure generating groove 3b, and dynamic pressure is generated between the contact end faces 3a and 9a with the rotating ring 3 and the stationary ring 9. As a result, the stationary ring 9 is pressed against the rotating ring 3 by the urging force of the spring 11.

  At this time, the rod 23 of the driving means 19 is moved forward, the seal ring 18 is brought close to the auxiliary ring 4 and the holder 8, and the gap 12 between the auxiliary ring 4 and the holder 8 is attached to the seal member 17 attached to the seal ring 18. As a result, the communication between the compressor impeller side and the outside is blocked, and the airtightness of the compressor impeller side can be maintained.

  For this reason, in a compressor targeting flammable, auxiliary combustion, and toxic gases, it is not necessary to operate the vacuum suction means when the compressor is stopped, and the power cost of the vacuum compression means can be reduced.

  The O-ring used for the seal member 17 is easy to become familiar with the auxiliary ring 4 and the holder 8 when the seal ring 18 is pushed out by the driving means 19 due to the cross-sectional shape and physical properties of the material (rubber), and the gap 12 is surely secured. Can be blocked. Further, if the groove 20 is a dovetail groove, the combination of the dovetail groove and the O-ring can prevent the seal member 17 from falling off the seal ring 18.

  Further, in a compressor (for example, a heat pump) used for a gas having a low boiling point, it is assumed that the refrigerant condenses when the compressor is stopped, the compressor impeller side becomes negative pressure, and the atmosphere enters the compressor. Can be eliminated by using the compressor seal device shown in FIGS. 1A, 1B, 2 and 3 that can maintain the airtightness on the impeller side.

  4 (a) and 4 (b) show a second example of the compressor seal device of the present invention. In the figure, the same reference numerals as those in FIGS. 1 (a), (b), 2 and 3 are used. The attached parts represent the same thing.

  In this compressor seal device, without using the sleeve 2 in FIGS. 1 (a) and 1 (b), the rotating ring 3 is directly fitted on the longitudinal intermediate portion 1 c of the rotating shaft 1, and the large diameter of the rotating shaft 1 is thereby increased. A restriction pin 5 parallel to the rotary shaft 1 is fitted into the part 1a and the rotary ring 3, and the restriction pin 5 prevents displacement of the rotary ring 3 in the circumferential direction with respect to the large diameter part 1a.

  Although the shape of the auxiliary ring 4 is different from that shown in FIGS. 1A and 1B, the auxiliary ring 4 is made of the rotating ring 3 by tightening the nut 6 screwed to the small diameter portion 1 b of the rotating shaft 1. It is not changed that it is pressed against the inner edge portion of the contact end face 3a.

  Accordingly, in the second example of the compressor seal device of the present invention, the rod 23 of the driving means 19 is advanced, and the seal ring 18 is moved closer to the auxiliary ring 4 and the holder 8 as in the first example described above. When the gap 12 between the auxiliary ring 4 and the holder 8 is sealed by the seal member 17 attached to the seal ring 18, the communication between the compressor impeller side and the outside is blocked, and the compressor impeller side is closed. Keep airtight.

1 Rotating shaft 3 Rotating ring 3b Dynamic pressure generating groove 4 Auxiliary ring 7 Compressor housing (housing)
8 Holder 9 Stationary ring 9a Contact end face 11 Spring 12 Gap 17 Seal member 18 Seal ring 19 Driving means 20 Groove

Claims (2)

A rotating ring mounted coaxially on the rotating shaft;
A stationary ring coaxially opposite the rotating ring;
A holder mounted on the housing so as to surround the stationary ring in the circumferential direction and supporting the stationary ring so as to be movable in the axial direction;
A spring for biasing the stationary ring toward the rotating ring,
The auxiliary ring is externally fitted to the rotating shaft so as to separate the gap from the inner peripheral surface of the holder,
In the compressor seal device provided with the dynamic pressure generating groove on one of the opposed surfaces of the rotating ring and the stationary ring,
The end surface on the counter-rotating ring side of the auxiliary ring is formed so as to be flush with the end surface on the counter-rotating ring side of the holder,
On the counter-rotating ring side of the auxiliary ring and the holder, a seal ring equipped with a seal member capable of sealing the gap between the auxiliary ring and the holder over the entire circumference is arranged,
When the compressor is in operation, the seal ring is pushed out toward the auxiliary ring and the holder so that the gap is sealed by the seal member. When the compressor is stopped, the seal ring is removed from the auxiliary ring and the holder so that the gap is not blocked by the seal member. A compressor seal device comprising a drive means for pulling apart.   The compressor seal device according to claim 1, wherein an O-ring is used as the seal member, and a groove into which the O-ring is fitted is formed in the seal ring.

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